1. Field of the Invention
This invention relates to fibrous activated carbon with a metal chelate compound supported thereon, a process for preparing the same, and a method of using the same. More particularly, it relates to fibrous activated carbon which is suitable for removal of toxic substances contained in gases, particularly ozone, a process for preparing the same, and a method of removing such toxic substances.
2. Description of the Prior Art
Ozone gas present in the air is responsible for air pollution because it produces oxidants in combination with NO.sub.x. Furthermore, ozone is produced by air planes flying through the stratosphere, or released from equipment in which corona discharge is involved, such as electrophotographers, ozone sterilizers, etc., equipment employing strong ultraviolet rays, and equipment in which a mercury lamp is used; the thus-produced ozones cause environmental problems.
The adverse influence of these ozones indicated below:
______________________________________ Exposure Conc. Exposure (ppm) Time Remarks ______________________________________ Damages on plants 0.03 8 hrs spinach, Japanese radish, tomato Cracks in elongated 0.02 1 hr Rubbers Perception of odor 0.02 only for 90% of people 5 minutes perceive. or less Sensitivity of test 0.08 to 3 hrs mice animals on bacterium 1.30 Irritation of 0.3 continuous respiratory organs, work for oppression of chest about 8 hrs Reduction of lung 0.5 3 hrs/day, recovery after function 6 days/ 6 weeks, no week, 12 change at 0.2 ppm weeks Reduction in lung 0.6 to 2 hrs breathing capacity 0.8 Increase in Resistance 0.1 to 1 hr respiratory 1.0 Violent coughing, 2.0 2 hrs Diffusion of power of attention Acute pulmonary 9.0 not clear tumor ______________________________________
The above results and tests therefore are described in (Kasseitan Kogyo(Activated Carbon Industry), Jukagaku Kogyo Tsushin Sha (1974)).
For the adsorption removal or decomposition removal of ozone contained in exhaust gases or in the air, a number of methods have been proposed, but materials which are very effective for the removal of ozone have not been available. For example, as an ozone removal or dcomposition agent, oxides of manganese, vanadium, iron, copper, nickel, chromium, cobalt, zinc, etc., catalysts prepared by supporting salts of such metals on granular or powdery activated carbon, and decomposition catalysts comprising such metallic elements are known. These agents, however, are low in removal efficiency and are not particularly effective materials as decomposition or removal agents. Additionally, activated carbon with palladium, platinum or silver supported thereon has been proposed. These activated carbons, however, have the disadvantages that the metals are expensive and that the activated carbons are low in ozone removal ratio and limited in durability.